Periodic 2nd order ordinary differential operators on R are known to have the edges of their spectra to occur only at the spectra of periodic and antiperiodic boundary value problems. The multi-dimensional analog of this property is false, as was shown in a 2007 paper by some of the authors of this article. However, one sometimes encounters the claims that in the case of a single periodicity (i...

Multi-periodic inventory control problems are mainly studied employing one of two assumptions. The first is the continuous review, where depending on the inventory level orders can be placed at any time, and the other is the periodic review, where orders can be placed only at the beginning of each period. In this paper, we relax these assumptions and assume that the time-periods between two rep...

Recent research interest in Karoo tick paralysis and its vector. Ixodes rubicundus, prompted this survey to determine the economic implications of this disease. The survey indicated relatively high losses caused by the condition, identified the stock involved and provided data on the incidence of paralysis and on the control methods employed. Recommendations are made to institute chemical contr...

In this article, multiple-product PVRP with pickup and delivery that is used widely in goods distribution or other service companies, especially by railways, was introduced. A mathematical formulation was provided for this problem. Each product had a set of vehicles which could carry the product and pickup and delivery could simultaneously occur. To solve the problem, two meta-heuristic methods...

In 1934 Biemond and Daniels first showed that the serum potassium level fell during paralytic episodes in patients with familial periodic paralysis. Subsequently a normokalaemic form of the disease was recognized (1951), while more recently a hyperkalaemic variety was described by Helweg-Larsen, Hauge, and Sagild (1955). This last type of periodic paralysis was given the name adynamia episodica...

Periodic paralysis is a rare disorder that causes episodes of severe muscle weakness that can be confused with other diseases, including epilepsy or myasthenia gravis. Hyperkalemic and hypokalemic paralysis are included within these diseases, the latter being divided into periodic paralysis (familial, thyrotoxic or sporadic) and non-periodic paralysis. In this regard, we present a case of famil...

based on some stationary periodic solutions and stationary soliton solutions, one studies the general solution for the relative lax system, and a number of exact solutions to the korteweg-de vries (kdv) equation are first constructed by the known darboux transformation, these solutions include double and triple singular periodic solutions as well as singular soliton solutions whose amplitude de...

OBJECTIVE To study the clinical characteristics of patients who suffer from hypokalemic periodic paralysis, as the presenting symptoms of thyrotoxicosis. MATERIAL AND METHOD A retrospective review of 29 patients who presented with the syndrome of hypokalemic periodic paralysis as the symptom of thyrotoxicosis at Ratchaburi Hospital between January 1,1995 and December 31, 2007. Patients'data, ...